M58PR256J datasheet(41/114 Pages) STMICROELECTRONICS

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M58PR256J, M58PR512J

Program operations

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5.3

Control Program mode

The Control Program mode is best suited to the storage of small, dynamic information.

Typically such data is contained within one Program Region and it will be frequently updated

and/or new data will be added to it.

Program Regions are configured in the Control Program mode by programming data only to

the ’A’ halves (bit A3= 0) of the Segments they contain. The ’B’ halves of the Segments must

remain erased, that is they should not contain any zero’s (see Figure 5: Program Regions

configured in Control or Object Program mode).

In a Program Region of 1KB configured in the Control Program mode, only 512B of data can

be stored.

When the Program Regions are configured in the Control Program mode, any program

method can be used: the Single Word or the Buffered Program methods.

Once a Program Region has been configured in the Control Program mode, if a zero is

written to a ’B’ half of one of its Segments, the program operation is terminated and an error

is generated. The Status Register Bits SR4 and SR9 are set to ‘1’. (Refer to Status Register

and to Table 12: Relationships between Program methods and Program modes, for details.)

The program mode of a Program Region configured in the Control Program mode can only

be changed by first erasing the Block that contains the Program Region.

5.4

Object Program mode

The Object Program mode is best suited to the storage of large, static information.

In a Program Region of 1KB configured in the Object Program mode, 1KB of data can be

stored.

When a Program Region is configured in the Object Program mode, it cannot be re-

programmed or have new data added without first erasing the entire Block that contains the

Program Region.

Program Regions are configured in the Object Program mode simply by programming at

least one bit in the ’B’ half (A3 = 1) of one of the Segments they contain.

If the programmed data is smaller than 1KB, the unused space remains in the erased state

(all the bits set to FFFFh), but can no longer be used to program data. See Figure 5:

Program Regions configured in Control or Object Program mode.

When the Program Regions are configured in the Object Program mode, only the Buffered

Program methods can be used. If an attempt is made to use the Single Word Program

method, the program operation is aborted and Status Register error bits SR4 and SR8 are

set to ‘1’. (Refer to Status Register and to Table 12: Relationships between Program

methods and Program modes, for details.)

M58PR256J Datasheet(PDF) 41 Page - STMicroelectronics